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Attracting beneficials

Posted 4/11/2016

Syrphid fly in cactus flower

Syrphid fly in cactus flower

Warm weather means that not only do we go out and play in our gardens, but other creatures are also interested in what we may be growing. Many of us prefer to garden organically, trying to use natural fertilizers and control pests with the least toxic methods. This is not to say that conventional approaches are wrong, but they are not the only means to grow good food and flowers.

Organic growing is not simply replacing one fertilizer with another or one pesticide with another. Instead, it means looking at the garden as a unique ecosystem, where fertility, water, plant selection and pest control are in balance.

Some of the best ways to garden using fewer standard chemical products are composting, attracting beneficial organisms, and paying close attention to the area — looking at individual plants as well as the garden as a whole.

Obtaining “beneficials” is probably the best way to deal with pest problems before they get out of control. While we may not always view them as a positive influence, they are an important way to keep pests from destroying an entire garden. There are three general categories of beneficials: pollinators, predators and parasites.

Has everyone heard about the need to protect our pollinators? Many insects, not only bees and butterflies, bring pollen from one plant to another, thus plants create fruit and seeds. Good gardeners understand the need to plant flowers that attract and nurture these essential arthropods. We sometimes have a negative opinion about insects, and lump them all together as “bugs,” completely inaccurate.

It is a terrible idea to get rid of all the insects in our gardens, as that would severely decrease the amount of fruit that we obtain.

Some insects are terribly destructive, however, causing gardeners to spend much time and energy keeping them from devastating the garden. Two hundred and fifty species of aphids (of the 4000 total) cause plant problems. They pierce the plant and draw out water as well as the valuable sugars that are present in its vascular system. They also produce “honeydew”, which can support the growth of fungi that shade leaves from needed sunshine. Aphids are also the main vector of plant viruses. It is fortunate that several other insects eat them.

Ladybugs are the first predators that may come to mind, but other insects are even more effective. Lacewing young look like tiny alligators as they eat aphids. The larvae of aphid predators (Aphidoletes aphidimyza) will devour large numbers, and the aphid parasite, Aphidius matricariae, lays its eggs inside aphids, killing them from the inside out.

This is only a small segment of the many pest-controlling insects. Many of these are attracted to savory herbs like caraway and fennel, as well as sunflowers. Think about placing them around the garden.

Finally, remember that many birds also eat insect pests, so provide water and brightly colored flowers. They may also visit your compost pile searching for insects.

With all of these biocontrols, you will have attractive flowers and foliage, and significantly fewer pests.

Angela O’Callaghan, Social Horticulture Specialist for University of Nevada Cooperative Extension, can be reached via email or call 702-257-5581.

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